1. Field of the Invention
In general, the present invention relates to stringed musical instruments. More particularly, the present invention relates to the bracing structures used to internally reinforce stringed musical instruments.
2. Prior Art Description
Many acoustic stringed musical instruments, such as guitars, violins, cellos, and the like, rely upon the body of the instrument to resonate and amplify the vibrations of the instrument's strings. Such wooden instruments typically are constructed with a hollow body that is covered by a soundboard. The soundboard faces the strings of the instrument and contains openings through which sound energy can pass into and out of the hollow body.
The hollow body typically is configured to have a backboard and side walls. The sound board is attached to the top of the side walls opposite the backboard. Various types of bracings are used to interconnect the backboard, side walls and soundboard at various junctions.
The soundboard is the part of a wooden instrument that resonates most in response to the vibrations of the instrument's strings. The soundboard needs to be as thin as possible to react to the string vibrations and create sound. However, the soundboard cannot be made so thin as to be weak. On a string instrument, the strings are strung across a bridge. The bridge presses against the soundboard of the instrument. The strings are under tension. This applies a downward force to the soundboard that must be borne by the soundboard.
In order to provide a soundboard that is both thin and strong, bracing is used to reinforce the soundboard. The traditional material for bracing is wood. Wood is used for its warm, tonal properties. However, wood has many disadvantages. Wood, being a natural material, can vary considerably within the same species. Wood may differ in strength, rigidity and tonal quality from piece-to-piece. Furthermore, wood is influenced by changes in temperature and humidity that causes the wood to expand and contract. In an instrument, the resulting dimensional changes affect the tone of the instrument.
There have been numerous designs using wood bracing to support the soundboard. The arrangement and dimension of the bracing can vary to produce different performance characteristics.
One of the earliest examples of wood bracing for soundboards is U.S. Pat. No. 72,591 to Joseph Bini, entitled Bracing For Guitar Sounding Boards, which describes a wood bracing for a soundboard which is in an “X” orientation, where the main bracing crosses over itself near the sound hole. Other bracing configurations are exemplified by U.S. Pat. No. 1,768,261 to Larson, entitled Guitar; U.S. Pat. No. 1,889,408 to Larson; entitled fretted Stringed Musical Instrument; U.S. Pat. No. 3,474,697 to Kaman, entitled Guitar Construction; U.S. Pat. No. 3,685,385 to Rendell, entitled Guitar; U.S. Pat. No. 3,892,159 to Houtsma, entitled Soundboard Bridge Configuration For Acoustic Guitar; U.S. Pat. No. 5,461,958 to Dresdner, entitled Acoustic Guitar Assembly; U.S. Pat. No. 5,952,592 to Teel, entitled Acoustic Guitar Assembly; and U.S. Pat. No. 6,166,308 to Lam, entitled Guitar Sound Board Assembly.
U.S. Pat. No. 3,656,395 to Kaman, entitled Guitar Construction, describes a wood brace arrangement where the main braces are oriented at an angle to the longitudinal axis of the soundboard, with a plurality of smaller braces oriented in a longitudinal manner.
U.S. Pat. No. 4,079,654 to Kasha, entitled Bracing Structure For Stringed Musical Instrument, describes a wood brace arrangement with a torsion bar positioned under the bridge to support the various loads and relieve other portions of the soundboard.
U.S. Pat. No. 3,974,730 to Adams, entitled Guitar Strut Assembly, describes an “X” brace arrangement with a pair of struts connecting the soundboard bracing with the backboard bracing.
U.S. Pat. No. 4,084,475 to Horowitz, entitled Guitar Construction, describes bracing arranged in a fan pattern from the sound hole to the heel end of the soundboard.
U.S. Pat. No. 4,178,827 to Mallory, entitled Stringed Instrument Construction, describes a wood brace arrangement with long main braces oriented longitudinally and positioned on either side of the sound hole.
U.S. Pat. No. 5,469,770 to Taylor, entitled Distributed Load Soundboard System, describes a brace arrangement where the braces intersect at a point below the bridge area.
U.S. Pat. No. 6,627,803 to Stephens, entitled Musical Instrument Brace, describes a wood brace design with holes in the brace to reduce the weight.
U.S. Pat. No. 6,943,283 to McPherson, entitled Bracing System For Stringed Instrument, describes a wood brace design with tunnels and valleys to create a 3D bracing system.
U.S. Patent Application Pub. No. US2005/0150346 to Wyman, entitled Stringed Musical Instrument, describes a laminated wood brace which is scalloped to provide less contact with the soundboard.
U.S. Pub. No. US2004/0231487 to Jagmin, entitled Acoustic Guitar Assembly, describes a bracing system made from graphite rods, preferably wrapped with spruce wood, which connect the neck to the soundboard.
All of the prior art bracing systems listed above use braces which are solid, and mostly constructed of wood. A disadvantage of solid braces is that they are heavy, and therefore reduce the vibrational response of the hollow body and soundboard. Furthermore, the production of wood bracing is a laborious process because wood must be cut into the desired shape while maintaining a consistent environment for temperature and humidity. Wood is also limited in terms of weight and stiffness. In general, a stiffer wood is heavier than a flexible wood. It is therefore difficult to make bracing from wood that is both stiff and lightweight.
A good bracing system for a string instrument is one that can offer a range of stiffness with the lightest weight possible. A good bracing system should also be versatile and easy to attach to the instrument.
A need therefore exists for a tubular bracing system that is lightweight, has good acoustic response, and can provide a range of stiffness to satisfy a multitude of needs. This need is met by the present invention as described and claimed below.